This invention relates generally to transfer sheets having (print) resist portions for resist printing.
Heretofore, a great variety of processes have been developed and proposed for coloring shaped materials and products. One of these processes is the so-called sublimation or heat transfer process,which ordinarily comprises: preparing a transfer sheet by forming a desired pattern with a composition containing as its predominant constituent a coloring agent such as a disperse dye or an oil-soluble dye which is highly sublimable on a desired support sheet structure; superposing a base material to which the transfer is to be made on the pattern face of this transfer sheet, and heating the resulting structure thereby to cause the above mentioned coloring agent to undergo sublimation thereby to cause the desired pattern to be transferred or transposed onto the base material, and thereby to color this material.
It is possible for the above mentioned sublimation to be accompanied partly by melting and evaporation. When the term "sublimation" is used hereinafter, it is intended to include partial melting and evaporation. A highly advantageous feature of the above described process is that, in comparison with conventional textile printing processes, process steps such as the printing (impressing) step, the steaming step, and the washing step can be abbreviated or simplified and, moreover, coloring of materials can be carried out in a dry heating manner.
For accomplishing resist printing in the above described sublimation or heat transfer process, various processes have heretofore been proposed. For example, one proposed process comprises first forming a resist layer comprising a water repellent such as a silicone resin on a sheet of paper, then printing this sheet with an aqueous ink containing a sublimable dye thereby to prepare a transfer sheet, and carrying out resist printing with the use of this transfer sheet. In this process, however, since an aqueous ink is used, swelling and wrinkling of the paper easily occur during the printing, and registering in multicolor printing is difficult. Another problem is that the preparation of the water-repellent ink is difficult, and, while relatively good results can be obtained with line drawings, soiling easily occurs particularly in the case of a picture of wide area.
In another example of a resist printing process proposed heretofore, a binder through which the sublimated vapor of the sublimable dye will not easily permeate is used. In this process, however, since a binder which will not mutually act with the sublimable dye is used, the resist action is weak, whereby the desired resist effect cannot be obtained unless the resist ink layer containing the binder is made extremely thick. For this reason, the printing of the resist printing ink is limited to a process, such as screen process printing, which can be carried out with a thick ink layer. By the screen process printing, however, the resolving power is poor, whereby fine resist printing patterns cannot be obtained. Furthermore, since the ink layer is thick, the drying gives rise to a difficulty in the production process, and, consequently, this becomes a cause of blocking. Still another problem is that, when a thick resist printing ink layer is provided on the transfer sheet, the close adhesion between the transfer sheet and the article to which the pattern is being transferred becomes insufficient during heat transfer, and nonununiform coloring easily occurs.
In still another known resist printing process, a resist agent comprising a water-soluble paste such as carboxymethyl cellulose is provided on a sublimable transfer sheet. According to a further proposal, a substance such as activated carbon is added to the above mentioned resist agent thereby to increase still more the resist effect. However, since the above mentioned water-soluble paste functions merely to physically shield off the sublimated dye, the resist action is weak, and, therefore, the resist layer must be made extremely thick. In this process the printing of the resist printing ink is limited to screen process printing, and various problems are encountered similarly as in the case of the second process described above.